[distcc] distcc multiple client users

[Brian Ristuccia]

Has any work been done in the area of optimizing job distribution with
multiple distcc client users? It seems the current system can result in
distcc servers being loaded to death if lots of people decide to compile at
the same time because the load leveling is done at the client side and one
user's clients do not know about another user's clients.

I see that as of distcc-2.5.x, there is now a -j option to the distcc
server. I suppose in the 3.x protocol this would cause the server to delay
returning a ready response on the TCP connection if the accepting the job
would cause the job limit to be exceeded. It seems like it would be possible
to get better performance especially in the case where large files are being
compiled, by having the client attempt in parallel to connect to several
distcc daemons, and then send the job to the one that responds ready first.
Even better if the ready response included the number of jobs already
running so that if multiple ready responses came back at almost exactly the
same time the best of them could be used.

It seems like it would be possible to implement the above system, perhaps in
a less than elegant form, with the current protocol. For example, if the
client were to try another distcc server if the first choice was not
listening, hung up the TCP connection right away, or sent a "go away"
message all that would be needed is to modify the server to stop listening
when it was too busy, hang up, or send a "go away" message.

Thoughts?

-- 
Brian Ristuccia
brian at ristuccia.com
bristucc at cs.uml.edu